[..] I'd like to add some functionality to the userblacklist module and therefore I'd like to modify the function check_blacklist ([string table]) because I need a check for the CALLER's URI _instead_ of the CALLEE's URI.

I want to change that for me, as I do deal with SPIT-prevention and I need a global_list to be able to block or delay some caller's URIs globally and whitelist others (like hospitals and stuff) for incoming calls. [..] I had a look at "userblacklist.c" and I guess that's the one to patch. My idea is to implement the changes and name the method "check_blacklist1()". Here it seems the the URI that's checked is stored in "req_number". [...] if ((parse_sip_msg_uri(msg) < 0) || (!msg->parsed_uri.user.s) || (msg->parsed_uri.user.len > MAXNUMBERLEN)) { LM_ERR("cannot parse msg URI\n"); return -1; } strncpy(req_number, msg->parsed_uri.user.s, msg->parsed_uri.user.len); [...] I guess I have to change "msg->parsed_uri.user.s" to something that returns the CALLER instead of the CALLEE!?

I had a look at the struct "sip_uri" (in msg_parser.h) because that's the type of variable "parsed_uri" and found the following... [..] So user is just a string (pointer to first char + length) and so it seems I have even to replace "parsed_uri" by something else. Then I had a look to struct "sip_msg" (in msg_parser.h) as it's the type of "msg" and next level of abstraction. There I found... [..] Another idea is to extend the parameter array of "check_blacklist()" so that one can pass the URI which has to be checked as an extra parameter. What do you think is the better way???

Furthermore I need a function that checks the global list for whitelisted entries. The flag "whitelist" is already present but there's no method to query it, as "check_blacklist()" returns true, when the prefix is whitelisted and the same when it's not on the list (so there's no way to distinguish between both possibilities yet)